Inhibiting mechanism of Alpiniae oxyphyllae fructus polysaccharide 3 against the replication of porcine epidemic diarrhea virus

Porcine epidemic diarrhea virus (PEDV) causes diarrhea, vomiting, and death in piglets. Our previous study has revealed the anti-PEDV activity of Alpiniae oxyphyllae fructus polysaccharide 3 (AOFP3). However, it is still unknown whether AOFP3 can inhibit the replication of PEDV. Therefore, the effect of AOFP3 on PEDV replication was investigated in the present study, along with analysis of viral RdRp activity and expression of hnRNP A1 by RNA polymerase activity assay in vitro, RIP assay, and Western blotting. The results showed that both the PEDV gene and protein levels in IPEC-J2 cells decreased with AOFP3 treatment. In addition, AOFP3 significantly reduced PEDV's replication by down-regulating the activity of PEDV RdRp and reducing the expression of hnRNP A1, whereas only the bind of RdRp to PEDV 3'UTR was inhibited in AOFP3 treated cells.

Alpiniae oxyphyllae fructus polysaccharide 3 inhibits porcine epidemic diarrhea virus entry into IPEC-J2 cells

Porcine epidemic diarrhea virus (PEDV) is deadly for suckling piglets and is a significant threat to most pig farms. Alpiniae oxyphyllae fructus polysaccharide 3 (AOFP3) shows antiviral activity against PEDV. However, the anti-PEDV mechanism of AOFP3 is unknown. Entering the host cell is important for viral infection, and many drugs play antiviral roles by inhibiting this process. To understand the antiviral mechanism of AOFP3 against PEDV, the effect of AOFP3 on PEDV entering IPEC-J2 cells was investigated in the present study. Real-time PCR and immunofluorescence were used to study the effect of AOFP3 on PEDV binding and penetrating IPEC-J2 cells. The effect of PEDV on AOFP3 attachment to IPEC-J2 cells was also investigated. Afterward, the effect of AOFP3 on PEDV spike (S) protein binding to porcine aminopeptidase was tested by using coimmunoprecipitation, and the effect of AOFP3 on the cholesterol level of IPEC-J2 cells was detected. The results showed that AOFP3 competitively inhibited PEDV adsorption on IPEC-J2 cells by blocking PEDV S protein binding to porcine aminopeptidase in IPEC-J2 cells. Furthermore, AOFP3 decreased PEDV penetration into host cells by decreasing the cholesterol level in IPEC-J2 cells.

Inhibition of porcine epidemic diarrhea virus by Alpiniae oxyphyllae fructus polysaccharide 3

Porcine epidemic diarrhea virus (PEDV) is a deadly pathogen that still plagues suckling piglets. However, there is still no anti-PEDV drug available in clinics. To develop potential anti-PEDV drugs, the antiviral activity of Alpiniae oxyphyllae fructus polysaccharide 3 (AOFP3) against PEDV infection in IPEC-J2 cells were assessed in our present study. The structural characterization of AOFP3 was studied by using HPAEC, GC-MS, FT-IR and NMR techniques. At the same time, the anti-PEDV activity of AOFP3 was investigated by performing RT-qPCR, Western blot and immunofluorescence assays. The results showed that AOFP3 (44.4 kDa) was composed of glucose and galacturonic acid at a molar ratio of 77.54:22.46 and consisted of →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, T-α-D-Glcp-(1→ and →4)-α-D-GalAp-(1→. AOFP3 significantly decreased PEDV titer in IPEC-J2 cells and prevented cellular damage of IPEC-J2 cells caused by PEDV infection. Furthermore, AOFP3 showed an antioxidative activity in inhibiting PEDV reproduction. Therefore, AOFP3 was expected to be a material of anti-PEDV drug.